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Stanley N. Cohen, MD

Stanley N. Cohen, MD

Kwoh-Ting Li Professor in the School of Medicine, Professor of Genetics and of Medicine
Postdoctoral Fellow, Albert Einstein College of Medicine, Bronx, NY, Molecular Biology (1967)
Senior Resident, Duke University Hospital, Durham, NC, Medicine (1965)
Clinical Associate, National Institute for Arthritis and Metabolic Diseases, National Institutes of Health, Bethesda, MD, Molecular Biology (1964)
Senior Assistant Surgeon, Reserve Corps of the Public Health Service, Molecular Biology (1964)
Resident, University of Michigan, Ann Arbor, MI, Medicine (1962)
Intern, Mount Sinai Hospital, New York, NY, Medicine (1961)
M.D., University of Pennsylvania, Philadelphia, PA, Medicine (1960)
Summer Student, Laboratory of Peter Medawar, University College London, UK, Transplantation Immunology (1959)
B.S., Rutgers University, New Brunswick, NJ, Biological Sciences (1956)
(650) 723-5315
Adapted from the National Library of Medicine website at

Stanley Norman Cohen is the Kwoh-Ting Li Professor in the School of Medicine, Professor of Genetics, and Professor of Medicine at Stanford University. Stan Cohen and UCSF Professor Herbert Boyer were the first scientists to clone DNA and to transplant genes from one living organism to another, an achievement often considered the birth of genetic engineering and DNA therapies.

In high school, his early scientific focus on physics shifted to biology and medicine, and after graduating from Rutgers University he entered the University of Pennsylvania School of Medicine, receiving his M.D. in 1960. Beyond Stan’s scientific interests, he was a debater, 5-string banjo player, published pop music composer, and avid skier and sailor.

Upon joining the Stanford faculty in 1968, he began experiments aimed at understanding genetic mechanisms that underlie antibiotic resistance in bacteria. To study plasmids spreading genes that confer resistance, it was necessary to generate and isolate bacterial populations that contain the progeny of single plasmid DNA molecules—i.e., to “clone” plasmid DNA. Cohen’s lab developed a method of doing this, using mechanical shearing to break plasmid DNA into fragments that might join together in different ways.

In 1972, Cohen met Boyer, whose lab was studying enzymes that cut plasmid DNA molecules more reproducibly than mechanical shearing. The cutting of DNA by one of these enzymes, called EcoRI, is site-specific and the DNA ends it generates can be glued together. They began a collaboration to construct and clone plasmids containing novel combinations of DNA fragments. Their first paper describing how new plasmids can be generated by joining together fragments derived from separate DNA molecules, “Construction of biologically functional bacterial plasmids in vitro” was published in 1973. In 1974, the Cohen lab reported that plasmid constructs containing DNA fragments from different bacterial species could also be combined and cloned, and that genes carried by such fragments could be expressed functionally in a foreign host. The same year, Stan’s paper with Boyer and others, “Replication and transcription of eukaryotic DNA in Escherichia coli” demonstrated that genes carried by even DNA from animal species could be isolated by cloning them in bacteria. Important from Stan’s perspective is that the use of DNA cloning methods could produce important insights about the workings of genes and cells in health and disease.

The DNA cloning approaches that Cohen and Boyer invented, which have become known as recombinant DNA technology, were patented by Stanford and UCSF in 1980, leading to what has become known as the biotechnology industry. Before its expiration in 1997 their seminal patent had 461 licensees, the most for any of the more than 30 patents that have resulted from work in the Cohen lab.

Subsequent scientific contributions made by Stan’s lab over multiple decades have extended to the areas of artificial intelligence in medicine, RNA decay, microvesicles, and host-oriented therapeutics. Most recently, his lab has focused on the biological role of nucleotide repeat sequences. His current research interests are indicated elsewhere on this website.

Stan has served on corporate boards and community service organizations. His lab has mentored almost 200 young scientists from around the world who have continued to contribute to medical science in academia, industry, and community service activities.

Cohen has received the Albert Lasker Basic Medical Research Award, the Wolf Foundation Prize, the Shaw Prize, the National Medal of Science, and the National Medal of Technology, and has been elected to the National Academies of Science and of Medicine and to the National Inventors’ Hall of Fame, among many other honors.
Funded Research Project: